LESSON What is breathing
15 respiration?
:
f %
r t, I
*-f-J ...
^r fT
t
'"4 '>-'-•
You need energy to live. So do birds, trees, and bacteria. All living things
need energy to carry out the life processes. And, there can be no life
without the life processes.
How do plants and animals get energy? The same way your car gets its
energy, by burning a fuel. Cars use gasoline as a fuel. Energy is released
when oxygen from the air combines with the gasoline in the engine.
Animals get energy by linking the oxygen they breathe with the food that
they eat. This important life process is called respiration [res-pun-RAYshun]. Respiration is the energy-producing process in living things. It is the
release of energy by combining oxygen with digested food (glucose).
Here is what happens:
Digested Food + Oxygen —* Energy and Waste Products
Respiration can also be shown in this way:
Glucose + Oxygen -> Energy + Water + Carbon Dioxide
(fuel)
(waste)
(waste)
In humans and many other animals, breathing is done by means of the
lungs. Breathing in is taking air into the lungs. Breathing out is forcing the
air out of your lungs.
• • yrt.st*. •••• *
A B O U T BREATHING A N D RESPIRATION
Breathing and respiration are related—but they are not the same. Breathing is necessary for
respiration to take place. Breathing is the mechanical process of taking oxygen into the body
and sending carbon dioxide out of the body.
•3» *"
\-v •
Figure A
Figure B
Breathing in (inhaling) sends oxygen into
the lungs.
Breathing out (exhaling) sends carbon dioxide waste out of the lungs.
Respiration takes place in every part of the
body. Respiration uses the oxygen that inhaling brings into the body.
energy
Try to answer these questions about respiration.
*
1. What brings the oxygen to all parts
>
r
h.
k
of the body? _
blood
2. What does respiration make that
living things need?
j\
ZL
6V\£lTQy
3. What waste materials does
respiration give off?
otloXiJe amdl u) after
oxygen plus digested
food gives energy
Figure C
91
BREATHIf
Breathing and respiration are related. But they are not the same.
Respiration is a chemical process. It happens in every cell. In respiration, digested food links
up with oxygen. This link-up produces the energy the cells need. .
., ..., ...
Breathing is a medianical [muh-KAN-ih-kul] action. Breathing is the movement of gases into
and out of the lungs.
: • *'
• '•;
Breathing is involuntary. You do it automatically without thinking. You breathe all the time.
You breathe when you are awake. You breathe when you are asleep. You breathe even when
you are unconscious!
How does breathing take place?
Many people believe that air in the lungs makes their chest move in and out when they
breathe. This is not true. In fact, the opposite is true. It is your chest size that makes air move
in and out of your lungs.
Your chest size changes when you breathe. It changes because of the actions of:
• your rib muscles, and
• your diaphragm [DY-uh-framJ muscle.
INHALING AND EXHALING
Figures D and E shorn what happens when you breathe. Study the diagrams carefully. Then answer the
questions.
Figure D Inhaling
Figure E Exhaling
1. When you inhale (see figure D),
a) The ribs move «.
faawwd, outward
b) the diaphragm moves .
upward, downward
c) There is now
•pace in the chest area, J j j v . , 1 . j ^
! f t 4
„..
move,
d) Air rushes
JJ2L
to fill this space.
in* out
•v-li-'. v-'tf-*^
2. When you exhale (Figure E),
a) the ribs move
1
HyPOf
inward, outward
b) the diaphragm moves
ooor
^
toward, downward
c) There is now _
_ space in the chest area.
d) Because of this pressure, air moves
into, out of
the hings.
MORE ABOUT BREATHING
Figure F
Why do you breathe?
Breathing is automatic. When the level of carbon dioxide in your blood increases, a message
goes to your brain. Then, your brain sends a message to your diaphragm and rib muscles to
move. You take a breath without thinking!
93
I N H A L I N G OR EXHALING? .
.
» s«.v- ^ ' ^ ^ ^ f ^ M
r
'
[
"
r
~ ~-
Each of the following goes either with inhaling or exhaling Place a checktfK)in the box where you
think it belongs.
-• .4&jj8fofi3Witt.
INHALING
1.
air moves out of the lungs
2.
air moves into the lungs
3.
ribs move out
4.
ribs move in
S.
chest space becomes smaller
6.
chest space becomes larger
7.
diaphragm moves down
8.
diaphragm moves up
EXHAUNG
V
y
y
s
W O R D SCRAMBLE
Below are several scrambled words you have used in this Lesson. Unscramble the words and write your
answers in the spaces provided.
1. ALEHEX
2. MUSELC
3. HINALE
4L GMPRHAAID
5. SBRI fitbs
94
tT*
$AnSc\t
X h h <t i t
b i a p K r ^ M
A B O U T THE RESPIRATORY TRACT
The path that air follows when we breathe is called the respiratory tract. It is shown in Figure
A. Study it. Then answer these questions or complete the sentences.
branching tuba*
Figure A Notice the enlarged segment of tne lung, tjum smmi
sac.
1. The respiratory tract starts with the
vru,^,*
MP^f^
2. The respiratory tract ends with millions of tiny . (X i T
x..
and the
fig>
SC»
Co.
/ l )
3. How many lungs does a person usually have? _
4. The parts of the respiratory tract are listed below. But they are not in order. Rewrite
them in the order in which air goes through the body.
(Vive*!* /
bronchi
q\rs<xcs
mouth and nose
L41MtO\
5. Each bronchus extends into a
air sacs
0
trachea
branching rubes
(broYctfialrs)
/u H
5
97
W H A T HAPPENS I N THE LUNGS?
The lungs have millions of air sacs. Air sacs
are also called alveoli [al-VEE-uh-ly], Alveoli are very tiny. You need a microscope to
see them.
oxygen IN
tocapBtaries
carbon dioxide
OUT of capillaries
capillaries
carbon dioxide,
heat, and water
OUT
Figure B
eh
1. Air that enters the air sacs is rich in _ £
OXygOV
i«iuwi uruKMjcc
. ^
%
2. Air that leaves the air sacs is rich in the gas.
'
oxvejen, carbon dioxide
3. Air sacs a* surrounded by
4.
The capillaries around the air sacs take in
J
J J
oxygenT carbon dioxide
'~
oxygen, carbon dioxide
5. List the three waste materials the lungs excrete.
^J^alo
better
k.a-i-
MATCHING
MflfcA each term in Column A with its description in Column B. Write the correct letter in the space
provided.
Column A
t
a.
i
b
t
4
98
Column B
1. exhaling
a) where gases are exchanged
2. inhaling
b) windpipe
3. air sacs
U6d 1!)
0 breathing in
4. trachea
d) surround the air sacs
5. capillaries
e) breathing out
FILL IN . H E B L A N K
Complete each statement using a term or terms from the list below. Write your answers in the spaces
provided. Some words may be used more Omn once.
alveoli
inhaling
mouth
windpipe
bronchi
exhale
nose
capillaries
,v
smaller and smaller ' V.'
l X ^ t i u n g in is called J ^ U a t r j ^
2. ^
3.
inhale through the
f^<?H.#H
.or
h
The trachea is the scientific name for the tO I Irsd p i
.
4. The trachea divides into two tubes called.
5.
In the lungs, the tubes branch into
6.
The lungs have millions of tiny air sacs called
7.
Air sacs have many _ C ^ L U 1 M 1 ? A .
8. We get rid of carbon dioxide waste when we
ftl*/eoti
.
f X ^ l e
LABEL THE D I A G R A M
Identify the parts of the respiratory system. Write the correct letter on the lines provided.
1. bronchi
A
2. nose ®~
3. branching tubes
4. mouth
5. air sacs
6.
trachea C
7.
hmg_^
Figure C
99